I'm not sure I follow. I want to get driving time I don't have it.
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gisnoviceJan 11 '11 at 0:27

I have a set of starting and ending locations, and PostGIS (therefore pgRouting). I gather that pgRouting allows me to find the shortest path between these points, but I need to get the quickest path in terms of travel time, and return the actual travel/drive time. Similar to the drive time estimate google maps gives.
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gisnoviceJan 11 '11 at 0:33

2

If your road network doesn't include information such as speed limits, stop lights/stop signs, turn or direction restrictions, etc, the calculated travel time will not be that accurate and could be wrong (for instance, if the route goes the wrong way down a one way street).
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mkennedyJan 11 '11 at 0:39

@gisnovice: pgRouting can find the path with the shortest length or (if you have the information) with the lowest costs (= travel time). If your graph doesn't contain the necessary info, you can't get good results.
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underdark♦Jan 11 '11 at 9:08

Seems so much easier to just use Google's API even though it's not 'the right way'. Out of curiosity, is there a common source for this information for US roadways? Google has to get the data somewhere.
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gisnoviceJan 12 '11 at 18:28

GRASS' v.net.iso (http://grass.osgeo.org/grass70/manuals/html70_user/v.net.iso.html) will also do this. Again, it takes the right data, and a bit of work to massage it into shape. However, I have done this successfully in the past, so it does work! I haven't used pgRouting, but hear it may be a bit more efficient!